How does a tree know when to wake up and grow?

Scientists have discovered that the older a tree gets, the faster it grows.

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Winter takes its toll on living things. To protect themselves from the elements, bears hibernate, and trees go dormant, but how does a tree know to wake up and grow again? Molecular geneticists from Michigan Technological University led a team that identified a gene that tells a poplar tree when winter ends and it's time to start growing again. The new study says it's a gene, just like a gene tells almost anything else alive when to wake up and grow. On a similar note, if you think of the ocean as a living entity, it too acts as if it were one living organism. You may wish to see the article, "Is the Earth a Sentient Living Organism? New Study May Provide the proof."

A team led by molecular geneticists from Michigan Technological University has identified and characterized a gene that tells a poplar tree when winter ends and a spring growing season begins. Victor Busov, a professor in Michigan Tech’s School of Forest Resources and Environmental Science; Yordan S. Yordanov, a research assistant professor at Michigan Tech; in collaboration with Cathleen Ma and Steven Strauss from Oregon State’s Department of Forest Ecosystems and Society published their findings online in the Proceedings of the National Academy of Sciences (PNAS) this week.

Using techniques of molecular genetics and genomics, the researchers modified the EBB1 gene to see what would happen when it is experimentally dialed up and down. They found that upregulation of the gene accelerates new growth or bud-burst, while downregulation of EBB1 delays bud-break, the name for the beginning of new growth. They also discovered that EBB1 is virtually undetectable while the tree is dormant but makes a dramatic reappearance just prior to and during bud-break.

“The absence of EBB1 during dormancy allows the tree to progress through the physiological, developmental and adaptive changes leading to dormancy,” Busov explains, according to the June 16, 2014 news release, "How does a tree know it's time to grow again?" Busov continues, “while the expression of EBB1 in specific cell layers prior to bud-break enables reactivation of growth in the cells that develop into shoots and leaves and re-entry into the active growth phase of the tree.”

Timing of the new growth is important economically and environmentally

Busov says the timing of the new growth after dormancy is environmentally and economically important, and its importance will grow as climate change escalates. “Late spring frosts can irreversibly damage the growing tissues, compromise growth vigor and make plants susceptible to insect damage,” he explains in the news release. “If trees grow too early, they expose themselves to these dangers. If they start too late, precious growing time will be lost. The timing has to be exactly right. The wild swings and unpredictability of climate extremes makes nailing the exact timing very difficult.

“It's foreseeable that in the near future forest and fruit trees may need our help to cope with climate change,” Busov went on to say, according to the news release. “The discovery of this gene is a small step in this direction. Scientists still have a long way to go to fully understand the process, but this discovery opens the door to an enigmatic world about which almost nothing was known. It can be used as a starting point for unraveling the mechanism behind it. By analyzing EBB1 and the physiological processes of which it is a part, it should be possible to gain new insights into control of dormancy release in perennial plants in general. This will enable novel approaches for population management, molecular breeding and genetic engineering of dormancy-associated traits.”

The research was supported in part by grants from the US Department of Energy, the US Department of Agriculture and industrial members of the Tree Biosafety and Genomics Research Cooperative at Oregon State University.

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Anne Hart, author of 91 paperback books, nutrition anthropology journalist, began writing full time as an independent journalist, novelist, and nonfiction book author starting on June 17, 1959. She holds a graduate degree specializing in professional writing (M.A. in English/writing). Her emphasis is on nutrition and health journalism, science writing, and culture in the media. Hart has written more than 5,000 Examiner.com articles since 2009.